Fixed incorrect example of quantize in README.md

[Aadniz]

README.md showed an example of quantize that doesn't work anymore.

$ ./quantize ./models/30B/ggml-model-f16.bin ./models/30B/ggml-model-q4.bin q4_1
llama_model_quantize: failed to quantize: invalid quantization type 0

main: failed to quantize model from './models/30B/ggml-model-f16.bin'

Changed example in README.md to show the options 2 - q4_0 and 3 - q4_1

[grencez]

Do you need to sync and rebuilt or something? I am able to run it as documented: ./quantize "path/to/ggml-model-f16.bin" "path/to/ggml-model-q4_0.bin" q4_0

[Aadniz]

My bad. did not run make after pulling